Gorou had two close friends growing up, and the two of them eventually got married. Their friendship continued, and soon they had a child, Sana, who became a fourth member of their happy friendship. Unfortunately, their good life was cut short when Sana's mother died, followed a year afterward by her father's death. Against the wishes of some relatives, Gorou has taken in their daughter Sana, the last surviving member of his group of friends. Gorou deals with troubles in his career and romantic relationships, while Sana goes through the usual troubles of a teenage girl. Gorou may be ill-prepared to be a guardian, and they may have little in common, but they will build a home together.